ARRT Equipment Operation and QA 5

Question 1

In digital radiography, which exposure indicator value system uses a scale where the target value is approximately 300, with acceptable range of 200-800?

Accepted Answer

Kodak EI system

Answer

The Kodak/Carestream Exposure Index (EI) system targets approximately 300 (with acceptable range 200-800), where higher numbers indicate higher detector exposure.

Question 2

A radiographer notices that images from a CR system appear consistently overexposed despite using correct technique. The most likely cause is:

Accepted Answer

The exposure indicator shows values consistently higher than the target

Answer

Consistently high exposure indicator values confirm that the detector is receiving excess radiation; this indicates a technique or AEC calibration issue causing overexposure.

Question 3

Which of the following describes the detective quantum efficiency (DQE) of an imaging system?

Accepted Answer

A measure of how efficiently a detector converts absorbed x-ray signal into useful image information relative to an ideal detector

Answer

DQE expresses how well a detector uses the incident x-ray signal; it combines quantum detection efficiency and noise performance, with a perfect detector having DQE = 1.0.

Question 4

During fluoroscopy, the image intensifier converts x-ray photons into a visible image through which sequence?

Accepted Answer

X-ray → cesium iodide input phosphor light → photocathode electrons → output phosphor

Answer

In an image intensifier, x-rays strike the cesium iodide (CsI) input phosphor producing light, which ejects electrons from the photocathode; electrons are accelerated and focused onto the output phosphor.

Question 5

What is the purpose of the daily sensitometric (sensitometry) QC test in a film-based department?

Accepted Answer

To monitor processor performance by evaluating base plus fog, speed, and contrast index on a processed strip

Answer

Daily sensitometry tracks film processor consistency by comparing base plus fog, speed index, and contrast index to established control values, detecting processor drift before it affects diagnostic images.

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT Equipment Operation and QA 5